Justin Bieber has some lil' friends who those close to him -- including his mom, Pattie Mallette -- insist are big trouble.

But he's a big boy now, and he's not gonna listen to anyone. They're not the boss of him!

For the uninitiated, Bieber's friends Lil Twist and Lil Za are the ones who have habits of banging up and speeding in Bieber's cars, freeloading at Bieber's mansion and terrorizing Bieber's neighbors.

TMZ reports that despite Bieber's camp begging him to ditch Lil Za and Lil Twist (especially after Lil Twist got arrested for a DUI in Bieber's Fisker Karma), the singer is pushing back hard.

Sources insist the Lils are a negative influence on Bieber, but Bieber insists they're "true friends" and refuses to drop them. This confirms what Bieber previously told Teen Vogue -- that Lil Za and Lil Twist are two of the very, very few people that he trusts, however unwise that may seem to outsiders.

The source also notes that Bieber's been surrounded by adults for his entire life and is embracing finally having a group of friends who are his own age.

Bieber's mom doesn't necessarily approve of his new pals, but considering the star is 19 and her cash cow, she can't really do much to stop him from hanging out with them, no matter how scumbaggy they seem.

Mallette did, however, try to defuse the talk of her son's troubles with mentions of his charitable ventures.

"I'm not naive to think that my child is perfect and making all the best decisions of his life," Mallette told 'Watch What Happens Live' (via PEOPLE).

"He knows what I disagree with and he knows all the things that I'm really proud of him for, too," she added. "I mean, people don't talk about all the great things he does every day. Every night before a show, he meets with Make-a-Wish kids. He goes to sick kids' hospitals. He visits with them [and] takes his time. He gives back to charities."

So how does she put up with her son acting like a tool belt? She sighed to 'Entertainment Tonight Canada,' "I just deal with whatever comes up, I think as you would if your kid was off to college and making decisions. You just … I just talk to him, I call him … and he knows what I think."

Yes, mama Bieber. He knows. And he clearly doesn't care. Can't you ground him or something?